The combination of polymers and inorganic filler materials is known for the production of composite materials with improved mechanical, thermal and barrier properties as compared to the unmodified polymer. A detailed discussion of composites can be found in Ajayan, P. M., Composite Science and Technology (Wiley, 2003).
The combination of polymers with metal oxides, also known as smectite clays or metal oxides, has been exploited as a means for the synthesis of composites. Comprehensive reviews on the subject are Alexandre and Dubois (2001) and Pinnavaia, T. J.; Beall, G. W. Polymer Clay Composites Wiley: New York, 2000. Smectite clays are described in Grim, R. E. Clay Mineralology 2nd edition; McGraw-Hill: New York 1968.
Several methods for the synthesis of polymer clay composites have been described in the art, for example Nylon/clay composites first described by Usuki et al. (1993). A. Usuki, et al., “Synthesis of nylon 6-clay hybrid”, J. Mater. Res., vol. 8, No. 5, May 1993, pp. 1179-1184. In this process nylon and montmorillonite are combined at high temperature.
A biodegradable thermoplastic material comprising a natural polymer, a plasticizer and an exfoliated clay having a layered structure and a cation exchange capacity of from 30-350 milliequivalents per 100 grams is described in U.S. Pat. No. 6,811,599 B2. The natural polymer is a polysaccharide.
A smectite clay modified with an organic chemical composition and a polymer is described in U.S. Pat. No. 6,521,690.
Composites formed from metal oxides and the synthetic homopolymer poly-L-lysine silicate composites have been described. (Krikorian, V. et al. J. Polym. Sci. B: Polym. Phys. 2002, 40, 2579).
Also known are composite materials formed by mixing hydroxyapatite (HA) and poly(epsilon-caprolactone-oxyethylene-epsilon-caprolactone) block copolymer (PCL-POE-PCL) to produce a resorbable material for biomedical applications, such as periodontal membranes. HA grains are surrounded by a film of PCL which grants close connection of HA grains within a copolymeric matrix. (Cerrai P. et al. J Mater Sci Mater Med. 1999; 10:283-9).
Another biomaterial application of composite materials is a penta-block-coupling polymer of warfarin-PEO-MDI-PEO-warfarin designed as a surface-modifying additive (SMA) for reversibly binding albumin by the simple coating of the novel SMA in SPU (Ji J et al. J Mater Sci Mater Med. 2002; 13:677-84).
Ordered nanoporous plastics with hydrophilic pore surfaces were prepared by the degradative removal of polylactide from a self-organized, multi-component composite containing two block copolymers: polystyrene-polylactide and polystyrene-polyethylene oxide. (Mao H., et al Faraday Discuss. 2005; 128:149-62).
Proteins make up the main structural elements of most organisms, using complex sequences of amino acids that lead to wide arrays of functionalities. One of the most intensely studied structural proteins, Bombyx mori silkworm silk, has generated significant interest because of its remarkable mechanical properties, which rival even spider silk. Elastin, another well-known structural protein, is found predominantly in the body's arterial walls, the lungs, intestines, and skin. Silk elastin like protein (SELP) is a recombinant protein consisting of alternating blocks of silk-like and elastin-like amino acids. The mechanical properties of recombinant proteins like SELP are often inferior or different to structural proteins found in nature.
The use of recombinant proteins in in vivo applications and in applications outside of the body may demand improved self-assembly of such recombinant proteins as well as improvements in a wide variety of protein properties.